ti－idf算法，实现对中文文档的检索，把多篇文档中的词，按照权值从小到大进行排列（词语以文本中的词库为准）--ti-idf algorithm, and Chinese document retrieval, word documents, in accordance with the right values ​ ​ from small to large to be ranked (thesaurus of words in the text shall prevail)-